Bangor-based voice teacher and choral director Molly Webster says singing is one of the most intimate and vulnerable things human beings can do together.

If that’s the case, then her choral group, Divisi, composed of 16 singers from the Bangor area, is one of the most intimate musical ensembles in Maine. With eight- or even 16-part harmonies, every singer works in close concert with the person singing next to them.

“When almost everyone is singing a different part, you really have to be aware of what every single other person is doing,” said Webster, 35, a native of Patten who has lived in Bangor for the past decade, teaching singing and conducting. “Sometimes I get a little verklempt at how beautiful it is.”

Those lush, difficult, compelling, a capella harmonies will be in full effect this Saturday, at Divisi’s annual holiday concert, set for 7 p.m. at the Bangor Arts Exchange on Exchange Street.

Gabor Degre | BDN

Gabor Degre | BDN

The Bangor-based choral group Divisi during a rehearsal at the Bangor Arts Exchange Monday evening.

The program combines contemporary choral works by composers such as Eric Whitacre, Eric William Barnum, Arvo Part and Joshua Shank, with a handful of more traditional holiday songs, and a few pop songs to round it out. With Divisi, Webster invites talented singers to audition, some of whom she recruits from other choruses and some of whom she knows by reputation.

“We do operate at a certain level, though I would say that not everyone has to be a classically trained singer,” Webster said. “You have to love to sing and want to work, and want to have fun with it as well.”

Though Divisi is in some ways a more traditionally “classical” group, the way the ensemble operates is much more like a rock band. The laid-back, gregarious Webster demands a lot of her singers, who range in age from 25 to 65 — but is just as happy to crack a joke as she is to criticize.

“I love everything I do and every group I work with, but Divisi is my baby,” Webster said. “To be able to sing this kind of music is a gift.”

Webster grew up in a musical family, with parents who sing and play instruments, and music always on in the house. She graduated from Katahdin High School in Stacyville in 2001, and studied vocal performance and music education at the University of Maine, where she finished her master’s degree in choral conducting in 2010.

There aren’t many people in the Bangor area who make a living as a musician, but Webster is one of them. Despite its small size, the region is rich with opportunities for singers of all skill levels, with community groups such as the New Renaissance Singers (which Webster also directs), the Bangor Community Chorus, various barbershop groups and the Bangor Area Children’s Choir. University of Maine-affiliated groups Euphony, the Oratorio Society and the Black Bear Men’s Chorus are also in the mix. And that’s not to mention the choirs at various churches and synagogues throughout the region. Webster does that, too. She started as music director at the Unitarian Universalist Church in Bangor just this year.

Gabor Degre | BDN

Gabor Degre | BDN

The Bangor-based choral group Divisi during a rehearsal at the Bangor Arts Exchange Monday evening.

Though groups like Divisi have benefited from the explosion in popularity of a capella singing — think Pentatonix or “Glee” — Webster enjoys having her group exist at the intersection of classical, pop and avant-garde. If the human voice can sing it, she wants to try it.

“The human voice is the ultimate instrument, because it’s you. If your finger slips on a trumpet, it’s different. Your voice is your body. That’s what makes it so powerful,” she said.